Abstract

The first observation of subnanosecond spectral hole burning is reported in tetraphenylporphine/p‐benzoquinone embedded in poly(methylmethacrylate) at liquid‐helium temperature. The hole formation mechanism is photoinduced one‐photon donor‐acceptor electron transfer, and is consistent with the mechanism predicted by the reaction exothermicity accompanying the reaction. Spectral holes burnt in the present system disappeared almost completely when the temperature was increased to 20 K.